Introduction to ‘Process Analytical Technology’ (PAT) for the Sampling Community
DOI: 10.62178/sst.004.002
Abstract
The evolution of Process Analytical Technology (PAT) from its roots in Process Analytical Chemistry (PAC) to its current integration with the Theory of Sampling (TOS) marks a pivotal transformation in pharmaceutical manufacturing. This article traces the historical, technical, and regulatory milestones that have shaped PAT into a comprehensive framework for ensuring product quality through real-time process understanding and control. It is also significant, and highly beneficial for society, that the modern PAT concept/framework has been found to be applicable in many other industry sectors. At the heart of this transformation lies the recognition that sampling is not merely a preparatory step but is in fact a critical determinant of analytical reliability. The incorporation of TOS principles, particularly the concepts of material heterogeneity, lot dimensionality, Total Sampling Error (TSE) and sampling process supremacy with regard to representativity, has elevated the role of sampling from being viewed as a procedural necessity to a scientifically governed critical discipline. The key to its adoption by regulators and industry is the implementation of control strategies for materials, sampling equipment (hardware and software), methods, training, and lifecycle management. When combined with chemometric modeling and multivariate calibration, TOS and PAT becomes powerful enablers of Quality by Design (QbD), continuous manufacturing (CM), and lifecycle management. Regulatory guidance from the Food and Drug Administration (FDA), International Council for Harmonisation (ICH), and international standardization bodies now reflect this integrated perspective, emphasizing the need for representative sampling, robust analytical procedures, and risk-based process validation. The convergence of PAC, PAT, and TOS provides a unique, powerful unified strategy for minimizing uncertainty, maximizing process efficiency, and ensuring regulatory compliance across the pharmaceutical product lifecycle. As the involved industries move forward, the continued refinement of sampling strategies, sensor technologies, and data analytics will continue to be essential. The future of PAT lies not only in further technological innovation but in the disciplined application of scientific principles that bridge the gap between relevant, optimized measurement (sampling-and-measurement) and meaning—between critical data and optimal decision-making. This article also presents a first, hopefully inspiring, scope of potential further PAT impact(s) in industry sectors that already rely on TOS.
Published in Issue 4 · December 2025
Citing this article
Ritchie, G. E. (2025). Introduction to ‘Process Analytical Technology’ (PAT) for the Sampling Community. Sampling Science & Technology, December 2025(4), 2-16. https://doi.org/10.62178/sst.004.002
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